docs: def vgcsUplinkGrant():
      """VGCS UPLINK GRANT Section 9.1.49"""
      a = TpPd(pd=0x6)
      b = MessageType(mesType=0x9)  # 00001001
      c = RrCause()
      d = RequestReference()
      e = TimingAdvance()
      packet = a / b / c / d / e
      return packet